US20040121750A1 - Wireless communication device haing variable gain device and method therefor - Google Patents

Abstract

Briefly, in accordance with one embodiment of the invention, a wireless device has an array of antennas. A signal is provided to one of the antenna by two variable gain amplifiers, one of which processes a signal that is shifted in phase compared to the signal processed by the other variable gain amplifier.

Description

BRIEF DESCRIPTION OF THE DRAWINGS
• The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:[0001]
• FIG. 1 is a schematic representation of a wireless device in accordance with an embodiment;[0002]
• FIG. 2 is a schematic representation of a portion of a wireless device in accordance with an alternative embodiment; and[0003]
• FIG. 3 is a schematic representation of a portion of a wireless device in accordance with an alternative embodiment.[0004]
• It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals have been repeated among the figures to indicate corresponding or analogous elements.[0005]
DETAILED DESCRIPTION
• In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.[0006]
• Some portions of the detailed description that follows are presented in terms of algorithms and symbolic representations of operations on data bits or binary digital signals within a computer memory. These algorithmic descriptions and representations may be the techniques used by those skilled in the data processing arts to convey the substance of their work to others skilled in the art.[0007]
• An algorithm is here, and generally, considered to be a self-consistent sequence of acts or operations leading to a desired result. These include physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers or the like. It should be understood, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities.[0008]
• Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities within the computing system's registers and/or memories into other data similarly represented as physical quantities within the computing system's memories, registers or other such information storage, transmission or display devices.[0009]
• Embodiments of the present invention may include apparatuses for performing the operations herein. An apparatus may be specially constructed for the desired purposes, or it may comprise a general purpose computing device selectively activated or reconfigured by a program stored in the device. Such a program may be stored on a storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, compact disc read only memories (CD-ROMs), magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), electrically programmable read-only memories (EPROMs), electrically erasable and programmable read only memories (EEPROMs), magnetic or optical cards, or any other type of media suitable for storing electronic instructions, and capable of being coupled to a system bus for a computing device.[0010]
• The processes and displays presented herein are not inherently related to any particular computing device or other apparatus. Various general purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct a more specialized apparatus to perform the desired method. The desired structure for a variety of these systems will appear from the description below. In addition, embodiments of the present invention are not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the invention as described herein. In addition, it should be understood that operations, capabilities, and features described herein may be implemented with any combination of hardware (discrete or integrated circuits) and software.[0011]
• In the following description and claims, the terms “coupled” and “connected,” along with their derivatives, may be used. It should be understood that these terms are not intended as synonyms for each other. Rather, in particular embodiments, “connected” may be used to indicate that two or more elements are in direct physical or electrical contact with each other. “Coupled” may mean that two or more elements are in direct physical or electrical contact. However, “coupled” may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other.[0012]
• It should be understood that embodiments of the present invention may be used in a variety of applications. Although the present invention is not limited in this respect, the devices disclosed herein may be used in many apparatuses such as in the transceivers, transmitters, and/or receivers of a radio system. Turning to FIG. 1, an[0013]embodiment100 in accordance with the present invention is described.Embodiment100 may comprise a portable computing orcommunication device50 such as a mobile communication device (e.g., cell phone), a two-way radio communication system, a one-way pager, a two-way pager, a personal communication system (PCS), a personal digital assistant (PDA), a portable computer, or the like. Alternative embodiments may include base stations, access points, or other wireless communication equipment in any network.
• Other embodiments may include, for example, any combination of laptop and portable commuters with wireless communication capability, web tablets, wireless headsets, instant messaging devices, MP3 players, digital cameras, and other devices that may receive and/or transmit information wirelessly. Although it should be understood that the scope and application of the present invention is in no way limited to these examples. Other embodiments of the present invention may include other computing systems that may or may not be portable or even involve communication systems such as, for example, desktop or portable computers, servers, network switching equipment, etc.[0014]
• In this particular embodiment,[0015]wireless communication device50 may include aprocessor10 that may execute instructions such as instructions stored in amemory40.Processor10 may be one of a variety of integrated circuits such as, for example, a microprocessor, a central processing unit (CPU), a digital signal processor, a microcontroller, a reduced instruction set computer (RISC), a complex instruction set computer (CISC), or the like, although the scope of the present invention is not limited by the particular design or functionality performed byprocessor10. In addition, in some alternative embodiments,wireless communication device50 may comprise multiple processors that may be of the same or different type.
• [0016]Wireless communication device50 may also comprisememory40 that may comprise any variety of volatile or non-volatile memory such as any of the types of storage media recited earlier, although this list is certainly not meant to be exhaustive and the scope of the present invention is not limited in this respect.Memory40 may comprise persistent memory to be used to store sets of instructions such as instructions associated with an application program, an operating system program, a communication protocol program, etc. For example, the instructions stored inmemory40 may be used to perform wireless communications, provide security functionality forwireless communication device50, user functionality such as calendaring, email, internet browsing, etc.
• [0017]Wireless communication device50 may also comprise adisplay20 to provide information to a user. Alternatively or in addition,wireless communication device50 may include other components such as input/output devices, audio outputs, etc. However it should be understood that the scope of the present invention is not limited so as to require any particular combination of components shown in FIG. 1.
• [0018]Wireless communication device50 may also include atransceiver85 to provide access to other devices, service, networks, etc that may be used to allowwireless communication device50 to communicate with other networks through a wireless link. As shown,transceiver85 may use an array of antennas made of up antennas86-88 to wirelessly communicate withnetwork60. It should be understood that the scope of the present invention is not limited to embodiments where communication is made to a single network, as alternative embodiments may provide communication to two or more networks. Furthermore, the scope of the present invention is not limited to embodiments having three antennas. Alternative embodiments may include devices that have one, two, or four or more antenna.
• In this particular embodiment,[0019]transceiver85 may include variable gain modulators76-78 that may be coupled to antennas86-88, respectively. As explained in more detail below, acontroller80 may be used to coordinate the transmission of signals via variable gain modulators76-78 so as to increase the relative strength of a transmitted signal (i.e. improved signal to noise ratio) in a particular or general direction, while reducing the effect of the signal in another particular or general direction, although the scope of the present invention is not limited in this respect. It should be understood that the scope of the present invention is not limited to applications involving the transmission of signals over an antenna array as the scope of the present invention includes alternative embodiments where variable gain modulators are used to receive signals as well. In yet other embodiments, variable gain modulators may be used to both transmit and receive signals.
• Although the scope of the present invention is not limited in this respect,[0020]communication transceiver85 may employ a variety of wireless communication protocols such as cellular (e.g. Code Division Multiple Access (CDMA) cellular radiotelephone communication systems, Global System for Mobile Communications (GSM) cellular radiotelephone systems, North American Digital Cellular (NADC) cellular radiotelephone systems, Time Division Multiple Access (TDMA) systems, Extended-TDMA (E-TDMA) cellular radiotelephone systems, third generation (3G) systems like Wide-band CDMA (WCDMA), CDMA-2000, and the like). In addition,wireless communication device50 may also include multiple transceivers that use different communication protocols.
• In addition,[0021]transceiver85 may use other protocols such as wireless local area network (WLAN), wide area network (WAN), or local area network (LAN) protocols such as the Industrial Electrical and Electronics Engineers (IEEE) 802.11 standard, Bluetooth™, infrared, etc. (Bluetooth is a registered trademark of the Bluetooth Special Interest Group).
• It should be understood that the scope of the present invention is not limited by the types of, the number of, or the frequency of the communication protocols that may be used by[0022]wireless communication device50. Furthermore, alternative embodiments may have more than two communication modules (either wired or wireless) and communication modules need not have separate antennae, and some or all may share a common antenna. It should also be understood thatwireless communication device50 may include other optional components such as, for example, a vocoder to encode voice data, etc.
• Referring now to FIG. 2, a particular embodiment for a[0023]variable gain modulator220 is provided.Variable gain modulator220 may be an example of how modulators76-77 (see FIG.1) may be implements, although it should be understood that every one of variable gain modulators has to be arranged in the same manner. It should also be understood thatvariable gain modulator200 and/or transceiver85 (see FIG. 1) may include other components such as low-noise amplifiers (LNA's), filters, oscillators, etc. which are not shown so as not to obscure the present embodiment.
• [0024]Variable gain modulator76 may comprise two signal processing paths (indicated with arrows210-211) that may be used to process aninput signal200 and provide anoutput signal290, although it should be understood that alternative embodiments may include more than two signal processing paths. Although the scope of the present invention is not limited in this respect,signal processing paths210 and211 may include a variable gain device250-251, such as a variable gain amplifier.Signal processing path211 may further include aphase shift element252.
• As shown in FIG. 2,[0025]input signal200 may be provided to bothvariable gain device250 andphase shift element252. Phase shift element may adjust the phase ofinput signal200 by an amount ranging from about 1 degree to 180 degrees to provide the input signal. In this particular embodiment, phase shift element may shiftinput signal200 by about 90 degrees. The shift in phase may be accomplished using a variety of techniques. For example,phase shift element252 may comprise a hybrid phase splitter or an LC phase shift network. Alternatively, phase shift element may comprise a transmission line of varying lengths. For example,phase shifting element252 may comprise a transmission line that is approximately one-fourth the length ofinput signal200 to adjust the phase ofinput signal200 by approximately 90 degrees. It should be understood that other lengths, and corresponding shifting ofinput signal200 are possible.
• In this particular embodiment, the output of[0026]phase shifting element252 may be provided to variable gain amplifier. Thus, the input ofvariable gain device251 is sifted with respect to the input ofvariable gain device250. In alternative embodiments, phase shifting element may be positioned aftervariable gain device251. Therefore,phase shifting element252 may receive the output ofvariable gain device251 and performs phase sifting afterinput signal200 has be processed byvariable gain device251. In such an alternative arrangement, the phase shifting element may provide the output signal ofsignal processing path211, although the scope of the present invention is not limited in this respect.
• Although the scope of the present invention is not limited in this respect, in this particular embodiment, the output of variable gain devices[0027]250-251 may be summed together by anadder270 that may represent adding the resulting signals fromsignal processing paths210 and211. Thus, the output of adder279 (i.e. output signal290) may represent the addition of two components: one component representing an amplified version ofinput signal200, the other representing an amplifier and phase shifted version ofinput signal200. Thus, as explained below, theoutput290 ofvariable gain modulator220 may be provided by altered by adjusting the gain of variable gain devices250-251.
• The amount or degree of gain applied by variable gain devices[0028]250-251 may be controlled bysignal lines260 and261, respectively. Although the scope of the present invention is not limited in this respect, signal lines260-261 may be provided and adjusted by a control unit such as, for example, controller80 (see FIG. 1). However, it should be understood that the scope of the present invention is not limited by how the gain of variable gain devices250-251 is adjusted or where the signals to make the adjustments originate. Furthermore, the scope of the present invention is not limited by the frequency at which adjustments in the gain are made as they could be made periodically, dynamically, or upon the occurrence of some other triggering mechanism occurring withinwireless communication device50.
• For example, a processor or state machine may be employed to monitor the signals being received/transmitted by antennas[0029]86-88 (see FIG. 1) and determine what adjustments should be made to the gain of variable gain devices250-251. Alternatively, adjustments may be made in accordance with a beam forming computation so thatwireless communication device50 may transmit a signal with the desired characteristics, is adapted to receive a signal with antennas86-88, or both.Wireless communication device50 may also optionally employ a feedback mechanism so that appropriate adjustments may be determined and made depending on the signals being transmitted and/or received in a real-time manner, although the scope of the present invention is not limited in this respect. IN alternative embodiments adjustments may be made with some delay to allow time for the signals to traversewireless communication device50 and/or to determine what changes, if any, should be made.
• In another embodiment of the present invention, variable gain modulators[0030]76-78 (see FIG. 1) may be operated or adjusted independently so as to alter the signals being transmitted by antennas86-88. Thus, a controller (e.g. controller80 may be coupled to variable gain modulators via a bus and may be adapted to provide control signals to variable gain modulators to adjust their operation independently of the others. In such embodiments, the signals may be digital or analog, and thus,transceiver85 may include the appropriate analog-to-digital (AD) or digital-to-analog (DA) converters. In yet another embodiment,transceiver85 may include two or more variable gain modulators couple to each antennae where one variable gain modulator may be used to process signals received by the antenna and another variable gain modulator may process the signal to be transmitted by the same antenna.
• Turning to FIG. 3, an alternative embodiment for a variable gain modulator is provided.[0031]Variable gain modulator330 may include a power splitter to provide input signal300 to asignal processing paths310 and311. Although the scope of the present invention is not limited in this respect,signal processing path310 may include avariable gain device331.Signal processing path311 may includephase shifting element252 such as one of those described above and avariable gain device332. Variable gain devices331-332 may include a variable gain amplifier, an attenuator, a bidirectional attenuator, or the like. Furthermore,variable gain device331 may be a device that is different thanvariable gain device332.
• If variable gain devices[0032]331-332 are a type of attenuator, this particular embodiment may provide a benefit in that thesignal processing paths310 and/or311 may be bidirectional so that variable gain modulator may be used to transmit and receive signals from an antenna, although the scope of the present invention is not limited in this respect.Variable gain modulator330 may also include apower splitter370 that may be used to sum or add the output of variable gain devices331-332 to provide an output signal390. It should be understood that in alternative embodiments,phase shifting element252 may be positioned so as to receive the output ofvariable gain device332 and provide the output ofsignal processing path311. In yet other embodiments, some or all the components shown in FIGS.2-3 may be interchanged, as desired, to provide a variable gain modulator having different characteristics.
• While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.[0033]

Claims (28)

1. A wireless communication device comprising:

an antenna array having a first antenna and a second antenna;

a phase shift element to provide an input signal to a first variable gain device; and

a second variable gain device, wherein an output signal of the first variable gain device is summed with an output signal of the second variable gain device and coupled to the first antenna.

2. The wireless communication device ofclaim 1, wherein the first variable gain device comprises a variable gain amplifier.

3. The wireless communication device ofclaim 1, wherein the wireless communication device is a device selected from the group comprising: a base station, a portable communication device, and an access point.

4. The wireless communication device ofclaim 1, wherein the phase shift element is adapted to shift the phase of a signal an amount ranging from about 1 degree to 180 degrees to provide the input signal.

5. The wireless communication device ofclaim 3, wherein the phase shift element is adapted to shift the phase of the signal about 90 degrees to provide the input signal.

6. The wireless communication device ofclaim 1, wherein the first variable gain device comprises an attenuator.

7. The wireless communication device ofclaim 6, wherein the first variable gain device comprises a bi-directional attenuator.

8. The wireless communication device ofclaim 1, further comprising a power combiner to sum the output of the first variable gain device and the out of the second variable gain device.

9. The wireless communication device ofclaim 1, wherein an input signal to the phase shift element is substantially equal to an input signal to the second variable gain device.

10. The wireless communication device ofclaim 1, wherein the phase shift element comprises a hybrid phase splitter or an inductor-capacitor (LC) phase shift network.

11. The wireless communication device ofclaim 1, wherein the phase shift element comprises a transmission line.

12. The wireless communication device ofclaim 11, wherein the transmission line has a length that is approximately one-quarter of the wavelength of an input signal to the second variable gain device.

13. The wireless communication device ofclaim 1, further comprising a power splitter, wherein the power splitter provides an input signal to the phase shift element and the second variable gain device.

14. The wireless communication device ofclaim 1, wherein the wireless communication device is adapted to dynamically vary the gain of the first variable gain device and the second variable gain device.

15. The wireless communication device ofclaim 14, wherein the wireless communication device is adapted to vary the gain of the first variable gain device independently of the second variable gain device.

16. An apparatus comprising:

a first antenna and a second antenna;

a first signal processing path comprising a first variable gain amplifier, wherein the first signal processing path receives an input signal and provides an output signal; and

a second signal processing path comprising a phase shifting element and second variable gain amplifier, wherein the second signal processing path receives an input signal and provides an output signal.

17. The apparatus ofclaim 16, wherein the output signal of the first signal processing path and the second signal processing path are coupled to the first antenna.

18. The apparatus ofclaim 16, wherein the phase shifting element is coupled to receive the input signal for the second signal processing path.

19. The apparatus ofclaim 16, wherein the phase shifting element is coupled to provide the output signal of the second signal processing path.

20. The apparatus ofclaim 16, further comprising:

a third signal processing path comprising a third variable gain amplifier, wherein the third signal processing path receives an input signal and provides an output signal; and

a fourth signal processing path comprising a phase shifting element and fourth variable gain amplifier, wherein the fourth signal processing path receives an input signal and provides an output signal.

21. The apparatus ofclaim 16, wherein the output signal of the first signal processing path is summed with the output signal of the second signal processing path and provided to the first antenna.

22. The apparatus ofclaim 21, wherein the output signal of the third signal processing path is summed with the output signal of the fourth signal processing path and provided to the second antenna.

23. A method of providing a signal to a first antenna in an array of antennas, the method comprising:

providing an input signal to a first signal processing path and a second signal processing path, the first signal processing path comprising a variable gain amplifier, the second signal processing path comprising a variable gain amplifier;

shifting the phase of a signal in the second signal processing path; and

summing an output of the first signal processing path and an output of the second signal processing path.

24. The method ofclaim 23, wherein shifting the phase of a signal includes shifting the phase of the input signal in the second signal processing path.

25. The method ofclaim 23, wherein shifting the phase of a signal provides the output signal of the second signal processing path.

26. An article comprising a storage medium having stored thereon instructions, that, when executed by a computing platform, results in:

providing an input signal to a first signal processing path and a second signal processing path, the first signal processing path comprising a variable gain amplifier, the second signal processing path comprising a variable gain amplifier;

shifting the phase of a signal in the second signal processing path; and

summing an output of the first signal processing path and an output of the second signal processing path.

27. The article ofclaim 26, wherein shifting the phase of a signal includes shifting the phase of the input signal in the second signal processing path.

28. The article ofclaim 26, wherein shifting the phase of a signal includes shifting the phase of the input signal in the second signal processing path.

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